Access Scheme for Future Mobile Radio Systems
R. Pon arun kumar.
The Interleaved Frequency Division Multiple Access (IFDMA) scheme is based on compression, repetition and subsequent user dependent frequency shift of a modulated signal. IFDMA is a promising candidate MA scheme for non adaptive transmission in the uplink of future mobile radio systems. In this paper it is shown that IFDMA can be regarded as unitary precoded OFDMA with interleaved subcarriers. It combines the advantages of single and multi carrier transmission such as low peak to average power ratio, orthogonality of the signals of different users even for transmission over a time dispersive channel. It is of low complexity for user separation and channel equalization that doesn't require any channel state information at the transmitter. It combines the advantages of both CDMA and OFDMA.
Currently, research on beyond 3rd and 4th generation (B3G/4G) mobile radio systems is in progress worldwide. A future mobile radio system will provide packet oriented data services carrying multi-media contents. Thus, on the one hand, properties like high spectral efficiency as well as high flexibility and granularity in terms of different data rates from a few kbit/s up to several Mbit/s are essential. On the other hand, low cost implementation and high power efficiency are important, especially for mobile terminals. Moreover, high user mobility has to be taken into account. The choice of the multiple access (MA) scheme has a great impact on the achievable features of a future cellular mobile radio system. The candidate MA schemes can be classified in single carrier based and multi carrier based MA schemes. Prominent representatives of single carrier based MA schemes are Time Division Multiple Access (TDMA),...